Oracle DBA Q & A page - 2

ORACLE DBA INTERVIEW QUESTIONS AND ANSWERS

                                     
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11. What are the various types of databases?

Multimedia database, Spatial database (Geographical Information System Database) , Real–time or Active Database, Data Warehouse or On–line Analytical Processing Database

12. Define Entity type and  set?

Entity type  defines a collection of entities that have same attribute.  Entity set is the collection of a particular  entity type that are  grouped  into an entity set 

13. What Is  snapshot?

Data in the database at a particular moment is known as Database State or Snapshot of the Database

14. How does a referential constraint differ from a unique constraint?

Referential constraints are concerned with how data in one table relates to data in another table, ensuring referential integrity between the two tables. Unique constraints ensure the integrity within a table by blocking duplicate values.

15. What command creates a grouping or collection of tables, views, and privileges?

The CREATE SCHEMA statement

16. What is the difference between SQL and PL/SQL?

SQL is a declarative language. PL/SQL is a procedural language that makes up for all the missing elements in SQL

17. What is another name for an SQL–invoked procedure?

Stored procedure

18. What are the differences between a column constraint and a table constraint?

Both types of constraints are defined in the table definition. A column constraint is included with the column definition, and a table constraint is included as a table element, similar to the way columns are defined as table elements

19. What is the difference between Delete and Truncate command in SQL?

Delete command and truncate command both will delete the data, however the truncate command can not be rolled back as delete can be. The delete command can be used for selected records using the where clause but with the truncate command we have to loose data. DELETE statement is a logged operation and hence takes more time then truncate.

20. What command is used to retrieve the results after a cursor has been opened?

The FETCH command

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